I have followed these issues closely, both at GetDpi and elsewhere:
http://www.l-camera-forum.com/topic/258959-state-of-s/http://www.l-camera-forum.com/topic/248514-leica-s-lens-af-issue/http://www.l-camera-forum.com/topic/266300-wtfs007-just-crapped-itself/I have strong opinions and recent experience on this subject by way of contrast with another company. My strong opinion is that Leica's quality control and, more importantly, customer service on the S system is completely unacceptable. My recent experience is as follows:
I have both an S system and a Phase One system. I love the S for its files, form factor, and lenses. I have not had any lens failures, but given the many people who have reported lens failures, I'm always on edge. I have, however, had an issue with an S body: specifically, my backup S006 was checked by a dealer and found to have sensor corrosion. It was sent to Leica Germany in mid-november. As of now -- early January -- there has been no word whatsoever on when I can expect it back. It took over 4 weeks to get from the US through German customers and, as of Dec. 14, still had not even arrived at Leica. No offer of a loaner in the meantime, although I asked Leica directly (not the dealer -- it's not his fault). No offer of a replacement camera rather than waiting a gazillion years for mine to be repaired and returned, although I asked that too. All I've received in response to my half dozen queries has basically been "please be patient; sorry for the inconvenience," and there's at least a week delay before I even get that kind of half-assed response. If this is all their new "professional service division" plans to do, it's very little indeed.
Contrast that with another recent experience with my Phase One XF. As XF owners know, the original style prism latch and battery door are problematic. They haven't caused me any big problems, but are of sufficient concern that I wanted to go ahead and get them fixed. I emailed my dealer (Digital Transitions) immediately before the holidays and got a response in less than 12 hours. They then offered to send me a loaner via priority shipping for me to use for the duration, and said that I should get mine back and repaired in a week to 10 days. They moved so fast that I haven't even managed to send mine in for repair yet (i'll do it today).
Now: I do not earn my primary income from photography, so I suppose I can "afford" the expected several month downtime for my S006 to be repaired and returned to me (yes: *several months* according to my dealer based on his past experience). But if I depended upon photography to make a living, there's no way I could do that. Notwithstanding the quality of the S system, I could not in good conscience at this point recommend to any professional photographer that s/he invest in the S system. Will portraits shot in natural light with the S007 and 100mm summicron at 2.0 look prettier than anything shot with my XF under similar conditions? Yep. But that doesn't matter if (a) the S doesn't work and (b) you need it to work so you can put bread on the table.
Edit: re-reading the above makes it sound like I don't like the files from my XF system. That's not the case: love them, in fact. Just pointing out that the S007 and 100mm summicron files at wide aperture are indeed pretty and, when that look is called for, prettier than what I can do with the XF. Which is why I have both. Now if Phase provided a Leica lens (or Contax lens) adapter for the XF body as I've repeatedly suggested, I'd be extremely happy and would ditch the S body. That wouldn't solve the problem that the S lenses that I'd use on the XF might at any moment crap out on me, but then I could at least divest myself from any further investments in S system bodies in the future. And, if I were a new buyer and such adapters were available, I wouldn't have bought the S body at all, purely for economic reasons.